Endovascular guidewire filter and methods of use

ABSTRACT

A filter device for temporary placement of a filter in an artery or vein is disclosed. The devices include (1) an elongate tubular member having a single or double side-wire loop, (2) an elongate member having a filter bonded to a circular rim joined by a plurality of tethers and an independently moveable tether, and (3) an elongate member having a parachute filter joined by a plurality of flexible struts. The filter conforms to the interior of a vessel wall when expanded and contracts to a consistent diameter without bunching when stowed. The filter devices may act as guidewires for guiding a therapeutic catheter to a region of interest within a vessel. Methods of using the filter device to entrap and remove embolic material from a vessel during endovascular procedures are also disclosed.

This application is a continuation application of U.S. application Ser.No. 10/039,102, filed on Jan. 4, 2002 , now U.S. Pat. No. 6,936,059which claims priority to U.S. Provisional Application No. 60/262,135,filed on Jan. 16, 2001.

FIELD OF THE INVENTION

The present invention relates generally to devices and methods forproviding temporary placement of a filter in a blood vessel. Moreparticularly, the invention provides a filter structure that conforms tothe interior vessel wall with minimum gap and can be collapsed tofacilitate its passage across large vascular lesions.

BACKGROUND OF THE INVENTION

Treatment of thrombotic or atherosclerotic lesions in blood vesselsusing an endovascular approach has recently proven to be an effectiveand reliable alternative to surgical intervention in selected patients.For example, directional atherectomy and percutaneous translumenalcoronary angioplasty (PTCA) with or without stent deployment are usefulin treating patients with coronary occlusion. Atherectomy physicallyremoves plaque by cutting, pulverizing, or shaving in atheroscleroticarteries using a catheter-deliverable endarterectomy device. Angioplastyenlarges the lumenal diameter of a stenotic vessel by exertingmechanical force on the vascular walls. In addition to usingangioplasty, stenting, and/or atherectomy on the coronary vasculature,these endovascular techniques have also proven useful in treating othervascular lesions in, for example, carotid artery stenosis, peripheralarterial occlusive disease (especially the aorta, the iliac artery, andthe femoral artery), renal artery stenosis caused by atherosclerosis orfibromuscular disease, superior vena cava syndrome, and occlusive iliacvein thrombosis resistant to thrombolysis.

It is well recognized that one of the complications associated withendovascular techniques is the dislodgment of embolic materialsgenerated during manipulation of the vessel, thereby causing occlusionof the narrower vessels downstream and ischemia or infarct of the organwhich the vessel supplies. In 1995, Waksman et al. disclosed that distalembolization is common after directional atherectomy in coronaryarteries and saphenous vein grafts. See Waksman et al., American HeartJournal 129(3):430-5 (1995), incorporated herein by reference in itsentirety. This study found that distal embolization occurs in 28% (31out of 111) of the patients undergoing atherectomy. In January 1999,Jordan, Jr. et al. disclosed that treatment of carotid stenosis usingpercutaneous angioplasty with stenting is associated with more thaneight times the rate of microemboli seen using carotid endarterectomy.See Jordan, Jr. et al., Cardiovascular surgery 7(1): 33-8 (1999),incorporated herein by reference in its entirety. Microemboli, asdetected by transcranial Doppler monitoring in this study, have beenshown to be a potential cause of stroke. The embolic materials includecalcium, intimal debris, atheromatous plaque, thrombi, and/or air.

Filters mounted to the distal end of guidewires have been proposed forentrapment of vascular emboli. A majority of these devices includes afilter which is attached to a guidewire and is mechanically actuated viastruts or a pre-shaped basket which deploys in the vessel. These filtersare typically mesh “parachutes” which are attached to the shaft of thewire at the distal end, and to wire struts which extend outward in aradial direction at their proximal end. The radial struts open theproximal end of the filter to the wall of the vessel. Blood flowingthrough the vessel is forced through the mesh thereby capturing embolicmaterial in the filter. These devices are self-directing and can beplaced intravascularly.

However, there are several disadvantages associated withguidewire-filtration. First, the steerability of the guidewire may bealtered as compared to conventional guidewires due to the size of thefilter, and the guidewire may bend, kink, and/or loop around in thevessel, making insertion of the filter through a complex vascular lesiondifficult. Secondly, the current filter designs, e.g., a basket or net,often fail to conform to the internal perimeter of the vessel, anddistal embolization can still occur despite the filter placement.Thirdly, as the filter is stowed, the filter material is gatheredtogether with “bunching” of the material at the perimeter, causinguncontrolled gathering and creating relatively large and poorly definedcrossing profiles. As a result, the current filter designs require largecapture sheaths to deploy and stow the filter.

What is needed are simple and safe blood filtering devices that conformto a patient's vessel wall to prevent distal embolization duringendovascular procedures, and provide easy steerability and a controlledclosure profile when contracted. Existing devices are inadequate forthis purpose.

SUMMARY OF THE INVENTION

The present invention provides devices and methods that protect apatient from distal embolization during endovascular procedures, e.g.,atherectomy, angioplasty, or stent-deployment. More specifically,endovascular filters that conform to the interior vessel wall withminimum gap are disclosed for capturing embolic material generatedduring a procedure in an artery or vein.

In one embodiment, the filter device includes a first elongate memberhaving a proximal end and a distal end. The first elongate member istypically a tubular member having first and second proximal ports locatea short distance proximal (1-3 cm, preferably 1 cm) from the distal end.The first port will generally be located approximately 180°circumferentially from the second port. One or two flexible members,e.g., wires made of stainless steel or plastic, each of which has aproximal end that extends through one of the first or second proximalports on the first elongate member, and a distal end that is attached tothe first elongate member at a position distal of the port.

In certain embodiments the distal end of one or both flexible memberspasses through first and second distal ports. Thus, the distal end ofeach flexible member is attached to the first elongate member within alumenal wall of the first elongate member after passing through thedistal port. The first proximal port on the tubular member is located ata circumferential position approximately 180° from the second proximalport, and the first distal port on the tubular member is located at acircumferential position approximately 180° from the second distal port.The first flexible member passes through one proximal port, and thenthrough the distal port that is 180° from the proximal port throughwhich the flexible member passes, and the same for the second flexiblemember. A filter is disposed about the first and second flexiblemembers, which are operable between an expanded condition and acontracted condition from the proximal end of the tubular member. Incertain embodiments, the filter is bonded at an edge to the first andthe second flexible members.

In some embodiments, the filter comprises a mesh as described in Tsugitaet al., U.S. Pat. No. 5,911,734, incorporated herein by reference in itsentirety. In other embodiments, the filter is made of a biocompatiblematerial, such as plastic (e.g., kynar, polyethylene tetrachloride,polyethylene, or mylar), having pores that are precision machined bylaser, etching, and/or chemical milling to provide less traumaticpathways for blood flow. Anticoagulants, such as heparin andheparinoids, may be applied to the filter to reduce thrombi formation.

In another embodiment, the device comprises first and second elongatemembers. The second elongate member is slideably disposed within a lumenof the first elongate member. The proximal ends of the first and secondflexible members are fixed to the second elongate member, and the distalends of the flexible members are fixed to the first elongate member. Theflexible members are operated by sliding the second elongate memberdistally within the first elongate member, thereby advancing theflexible members through the proximal ports and placing the filter in anexpanded state.

In another embodiment, the filter device includes a flexible loop havinga first end, a second end, and an intermediate section positioned near adistal port of the elongate tubular member. A filter is disposed aboutthe intermediate section. The first end is operated to advance theflexible loop distally. The intermediate section of the loop extendsthrough the distal port and into a lumen of a vessel for deployment ofthe filter. In some embodiments, a tether, which is attached at one endto the intermediate section of the loop, restrains the intermediatesection and changes the orientation of a plane described by the loop,preferably orienting the plane perpendicular to the axis of the vessel.

In another embodiment, a plurality of tethers are coupled at a first endto the distal end of the elongate member, and the second end of each ofthe tethers is coupled to the edge of a parachute filter. In certainembodiments the edge of the filter is mounted about a circular rim. Anindependently moveable tether is also coupled to the filter edge or thecircular rim and is operable at a proximal end. A capture sheath,slideably disposed over the filter and the circular rim, assists instowing the filter and prevents accidental dislodgment of embolicmaterial during filter closure. The circular rim or filter edge can berotated into alignment substantially parallel with the elongate memberand capture sheath by withdrawing proximally the independently moveabletether. In some embodiments, the circular rim is constructed of asuperelastic material, e.g., nitinol. This alignment enables the capturesheath to cover the filter and circular rim to assist with removal ofthe filter from the vessel.

In another embodiment, the filter is attached to the elongate member bya plurality of flexible struts. Each of the flexible struts is coupledat a first end to the distal end of the elongate member and coupled at asecond end to the filter. The filter is contracted by rotating theelongate member, which in turn winds the flexible struts. A capturesheath is disposed about the elongate member and the filter for stowageof the filter. As the flexible struts wind, the filter is closed, andthe capture sheath is able to cover the flexible struts and filter toassist in removal from the vessel.

The filter devices of the present invention are most useful in capturingembolic debris generated during endovascular procedures within acoronary artery, aorta, common carotid artery, external and internalcarotid arteries, brachiocephalic trunk, middle cerebral artery, basilarartery, vertebral artery, subclavian artery, brachial artery, axillaryartery, iliac artery, renal artery, femoral artery, popliteal artery,celiac artery, superior mesenteric artery, inferior mesenteric artery,anterior tibial artery, posterior tibial artery, and all other arteriescarrying oxygenated blood. The filter devices are also useful inpreventing distal embolization in the venous circulation, including thesuperior vena cava, inferior vena cava, external and internal jugularveins, brachiocephalic vein, pulmonary artery, subclavian vein, brachialvein, axillary vein, iliac vein, renal vein, femoral vein, profundafemoris vein, great saphenous vein, portal vein, splenic vein, hepaticvein, and azygous vein.

In a first method of using the filter device having first and secondflexible members, the filter is placed in a contracted state. The distalend of the tubular member is inserted percutaneously through an arteryor vein and advanced into or beyond a region of interest, typically astenotic lesion caused by buildup of atherosclerotic plaque and/orthrombi. The filter is then expanded downstream of the vascularocclusion by operating the first and second flexible members. In thisway, the filter structure conforms to the interior vessel wall withminimum gap, as the elongate tubular member lies against the luminalwall of the vessel. The elongate tubular member then acts as a platform,or guidewire, to guide therapeutic instruments to operate on thestenosis within the region of interest. After the stenotic lesion isremoved by endovascular procedure(s), e.g., angioplasty, atherectomy, orstent deployment, the filter is collapsed and removed from the vessel,together with the captured embolic debris. When the filter is stowed,the flexible members are tightened against the tubular member andconstricted by a capture sheath advanced distally over the filter duringclosure, creating a controlled closure of the filter. In this way,bunching of the filter and undesired release of the captured embolicdebris are avoided.

In another method, using the filter device having a flexible loop, thedistal end of the elongate tubular member is positioned at a region ofinterest within a patient's vessel. The first end of the loop isadvanced distally, advancing the intermediate section through the distalport until the filter covers the lumen of the vessel. The elongatetubular member is then used to guide therapeutic catheters to operate onthe stenosis at the region of interest.

In another method, using the parachute filter device with or without acircular rim coupled to the elongate member by a plurality of tethers,the distal end of the elongate member is first positioned within aregion of interest. The capture sheath is withdrawn to release thecircular rim and filter within the region of interest. Therapeuticcatheters are then deployed upstream the filter. To stow the filter, theindependently moveable tether is withdrawn to rotate the circular rim sothat a plane defined by the circular rim or mouth of the filter isparallel to a line defined by the elongate member, thereby bringing therim into alignment with the elongate member and capture sheath. Thecapture sheath is then advanced over the circular rim and filter,wherein the mouth of the filter and/or the circular rim collapses to asubstantially oval shape.

In another method, using the filter device having a filter coupled tothe elongate member by a plurality of flexible struts, the distal end ofthe elongate member is advanced to a region of interest within apatient's vessel. The capture sheath is withdrawn to release the filter,thereby expanding the filter within the region of interest. Aftercompletion of endovascular procedures, the elongate member is rotated,thereby winding the plurality of flexible struts to contract the filter.The capture sheath is advanced distally to cover the wound flexiblestruts and the filter, thereby providing tight stowage of the filter andpreventing accidental release of captured emboli.

It will be understood that there are several advantages to using thefilter devices and methods disclosed herein for capturing and removingembolic debris during endovascular procedures. For example, the filterdevices (1) are particularly well suited for temporary filtration ofblood in any vessel to entrap embolic debris, thereby minimizingneurologic, cognitive, and cardiac complications associated with distalembolization, (2) conform to the interior vessel wall with minimum gap,(3) can be collapsed to a uniform and predictable size, (4) can bedelivered over a guidewire as a rapid exchange device, (5) can bedelivered through a lumen of an angioplasty or stent deployment device,(6) may include an atraumatic distal tip to minimize vessel wall injury,(7) enable an operator to steer and deploy the filter without kinking,bending, and/or looping of the catheter because of the small size ratioof filter to catheter, (8) can pass a large occluding lesion due totheir small diameter when collapsed, (9) can be used as a guidewire overwhich a therapeutic catheter may be advanced, and (10) can be used inadult and pediatric patients.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts an embodiment of a filter device having a doubleside-wire loop.

FIG. 1B depicts the filter device of FIG. 1A partially expanded.

FIG. 1C depicts the filter device of FIG. 1B further expanded.

FIG. 1D depicts the filter device of FIG. 1C fully expanded.

FIG. 1E depicts an end view of the filter device of FIG. 1D.

FIG. 1F depicts an top view of the filter device of FIG. 1D.

FIG. 1G depicts a collapsed filter mounted on the filter device of FIG.1A.

FIG. 1H depicts the filter of FIG. 1G expanded by operation of first andsecond side-wire loops.

FIG. 2 depicts the filter device of FIG. 1H deployed in the left commoncarotid artery.

FIG. 3A depicts an embodiment of a filter device having an expandableflexible loop.

FIG. 3B depicts the filter device of FIG. 3A partially expanded.

FIG. 3C depicts the filter device of FIG. 3B fully expanded.

FIG. 3D depicts the filter device of FIG. 3C expanded with adjustedorientation.

FIG. 3E depicts the filter device of FIG. 3D disposed within a vessel.

FIG. 3F depicts a filter device disposed about the flexible loop of FIG.3E.

FIG. 4A depicts an embodiment of a filter device having an independentlymoveable tether.

FIG. 4B depicts a capture sheath.

FIG. 4C depicts the capture sheath of FIG. 4B covering the filter ofFIG. 4A.

FIG. 4D depicts partial removal of the capture sheath of FIG. 4C.

FIG. 4E depicts further removal of the capture sheath of FIG. 4D.

FIG. 4F depicts complete removal of the capture sheath of FIG. 4E.

FIG. 4G depicts operation of the independently moveable tether toreorient the circular rim.

FIG. 4H depicts advancement of the capture sheath over the elongatemember of FIG. 4G.

FIG. 4I depicts further advancement of the capture sheath to partiallycover the circular rim of FIG. 4H.

FIG. 4J depicts complete coverage of the circular rim by the capturesheath of FIG. 4I.

FIG. 5A depicts the filter device of FIG. 4C inserted within a stenoticregion of a vessel.

FIG. 5B depicts the filter device of FIG. 5A deployed downstream of thestenotic region.

FIG. 5C depicts an angioplasty catheter advanced over the filter deviceof FIG. 5B.

FIG. 5D depicts retrieval of the filter device of FIG. 5C using acapture sheath.

FIG. 6A depicts an embodiment of a filter device having a parachutefilter coupled by flexible struts to an elongate member.

FIG. 6B depicts a capture sheath.

FIG. 6C depicts the capture sheath of FIG. 6B covering the filter ofFIG. 6A.

FIG. 6D depicts partial removal of the capture sheath of FIG. 6C.

FIG. 6E depicts further removal of the capture sheath of FIG. 6D.

FIG. 6F depicts full expansion of the parachute filter of FIG. 6E.

FIG. 6G depicts advancement of the capture sheath over the flexiblestruts of FIG. 6F.

FIG. 6H depicts rotation of the elongate member and winding of theflexible struts of FIG. 6G.

FIG. 6I depicts complete coverage of the wound flexible struts andfilter of FIG. 6H.

FIG. 7A depicts the filter device of FIG. 6C inserted through a lumen ofa therapeutic catheter deployed within a stenotic lesion of a vessel.

FIG. 7B depicts the filter device of FIG. 7A deployed downstream of thestenotic region.

FIG. 7C depicts closure of the flexible struts and filter by winding ofthe struts and advancement of the capture sheath.

FIG. 8 depicts various percutaneous insertion sites for the filterdevices described herein.

DETAILED DESCRIPTION

A filter device for temporary placement in a vessel, either an artery orvein, is provided as depicted in FIGS. 1A through 1H. FIG. 1A showselongate tubular member 10 having proximal ports 25 and distal ports 26located at a distal region. Proximal ports 25 are locatedcircumferentially approximately 180° from each other. Distal ports 25are also located circumferentially approximately 180° from each other.The circumferential positioning, however, may vary between 90° and 270°,more preferably 100° to 260°, more preferably 110° to 250°, morepreferably 120° to 240°, more preferably 130° to 230°, more preferably140° to 220°, more preferably 150° to 210°, more preferably 160° to200°, more preferably 170° to 190°, most preferably approximately 180°.

A first flexible member 20 passes through port 25 at a proximal end,crosses 180° over elongate member 10 at point 21, and either is coupledexternally at the distal end of elongate member 10 (not shown), orpasses through distal port 26 and is coupled to the luminal wall at theinterior of elongate member 10. It will be understood that firstflexible member 20 passes through proximal port 25 on one side ofelongate member 10, and passes through distal port 26 on the oppositeside of the elongate member.

One flexible member or two flexible members may be used. FIGS. 1A to 1Hdepict the use of two flexible members 20 and 22. As shown in FIG. 1F,the second flexible member 22 passes through a second port 25 at aproximal end, crosses 180° over elongate member 10 in a directionopposite to that of first flexible member 20, and either is coupledexternally at the distal end of elongate member 10 (not shown), orpasses through a second distal port 26 and is coupled to the luminalwall at the interior of elongate member 10. It will be understood thatsecond flexible member 22 passes through a second proximal port 25 onone side of elongate member 10, and passes through a second distal port26 on the opposite side of the elongate member.

First and second flexible members 20 and 22 may extend to the proximalend of elongate tubular member 10, or may be attached to the distal endof elongate member 15 which is slideably disposed within the lumen oftubular member 10, as depicted in FIG. 1A. When elongate member 15 isadvanced distally as shown in FIGS. 1B, 1C, and 1D, flexible members 20and 22 advance through proximal ports 25 to progressively enlarge loopsextending radially about tubular member 10. FIG. 1E shows an end view oftubular member 10 and flexible member 20 extending from a proximal port25 and through a distal port 26, and defining a circle that includestubular member 10.

FIG. 1F shows a top view of elongate tubular member 10, elongate member15, and the double side-wire loop structure defined by first and secondflexible member 20 and 22. FIG. 1G depicts filter structure 30 disposedabout the side-wire loop structure before expansion. FIG. 1H shows anexpanded side-wire loop structure having filter 30 disposed thereon, thefilter having opening 31 that receives blood flow and emboli, and allowspassage of blood but retains emboli in the filter. The filter maycomprise a mesh material or a thin film with laser cut holes. Theconstruction and use of a filter mesh have been thoroughly discussed inearlier applications including Barbut et al., U.S. application Ser. No.08/533,137, filed Nov. 7, 1995, Barbut et al., U.S. application Ser. No.08/580,223, filed Dec. 28, 1995, Barbut et al., U.S. application Ser.No. 08/584,759, filed Jan. 9, 1996, Barbut et al., U.S. Pat. No.5,769,816, Barbut et al., U.S. application Ser. No. 08/645,762, filedMay 14, 1996, and, Barbut et al., U.S. Pat. No. 5,662,671, and thecontents of each of these prior disclosures are expressly incorporatedherein by reference in their entirety.

Where a thin film with laser cut holes is used, the thin film willinclude any biocompatible material, such as plastic (e.g., kynar,polyethylene tetrachloride, polyethylene, or mylar). The processing usedto create pores in the thin film can be either laser or chemicaletching, stamping, or cutting by hand. The pores are precision machinedinto the filter material, thereby providing less traumatic pathways forblood flow and minimizing activation of the intravascular clottingprocess. Anticoagulants, such as heparin and heparinoids, may be appliedto the thin film to reduce thrombi formation. In the embodiments of thefilter devices that are to be used in the aorta, pore size is 500 μm orless, more preferably 400 μm or less, more preferably 300 μm or less,more preferably 200 μm or less, more preferably 100 μm or less, morepreferably 50 μm or less and usually larger than at least a red bloodcell. Typical dimensions include pore size of 20-500 μm, and a petalthickness of 0.0005-0.003 inches.

FIG. 2 shows the double side-wire loop filter of FIGS. 1A through 1Hdeployed within left common carotid artery 102. Elongate tubular member10 is advanced to position through left subclavian artery 106. Tubularmember 10 includes atraumatic tip 29 at a distal end to reduce vesseltrauma and better navigate tight stenotic lesion 100. Filter 30 expandsabout flexible members 20 and 22 within the lumen of left common carotidartery 102 to capture dislodged embolic material, e.g., calcium,atheromatous plaque, thrombi, air, and vascular debris.

FIGS. 3A through 3F depict another embodiment of a filter device.Elongate tubular member 40 contains a loop of wire or other flexiblematerial 45 within its lumen. Wire 45 has a first end, a second end, andintermediate region 47 shown in FIG. 3A. Optional tether 50 is joined tointermediate section 47 at position 46. A filter (not shown for clarity)is attached to the intermediate section of the wire loop and containedwithin the lumen of tubular member 40 before deployment. The firstand/or second end of flexible loop 45 is advanced distally, causingintermediate section 47 to extend through the distal port on tubularmember 40 into the lumen of the vessel, as shown in FIGS. 3B and 3C.

As loop 45 is advanced distally out of its containment lumen, it growsin diameter. The flexible loop (along with attached filter) continues togrow until it nears the diameter of the vessel in which the filter isbeing deployed. At this point, tether 50 restrains wire loop 45, and isoperated independently as shown in FIG. 3D to change the orientation ofthe plane described by the loop. The plane of loop 45 is substantiallyparallel to the axis of tubular member 40 shown in FIG. 3C, but withoperation of tether 50 as shown in FIG. 3E, the plane described by theloop is substantially perpendicular to the longitudinal axis of tubularmember 40 and vessel 101. FIG. 3F shows final deployment of wire loop 45and filter 30 within vessel 101. Loop 45 describes a plane that issubstantially perpendicular to the longitudinal axis of the vessel, andthe loop has reached a diameter such that the loop is in complete ornearly complete contact with the luminal wall of the vessel, thusforcing all or nearly all blood to flow through the filter material.

According to this embodiment, tubular member 40 may be constructed of adiameter of 0.04 inches, including the filter contained within thelumen, so that it can be delivered through a guidewire lumen of apercutaneous transluminal angioplasty balloon or stent deliverycatheter. This device may also be configured so that the distal tip oftubular member 40 has a diameter of approximately 0.035 inches (orlarger) to allow for ease of packaging of the filter and its wire loopwithin the containment lumen. The entire device would include a distalfilter containment tip of tubular member 40 having a 0.035 inch outerdiameter (OD) with an attached 0.014 inch diameter wire extendingproximally from the tip. In use, the 0.014 inch diameter segment wouldbe covered by a removable sheath having 0.035 inch OD. After deliveryand deployment of the filter, the sheath is removed, leaving the 0.014inch diameter wire in place, and holding the filter the 0.014 inchdiameter wire is then used to facilitate treatment of the vessel byadvancing over the wire standard therapeutic over the wire catheterdevices.

The wire loop can be made (preformed) of shape memory alloys, such asnitinol, and may be designed so that the tether is not needed to achieveproper orientation for filter deployment. The loop may alternatively bemade of plastic or any other material that would facilitate deploymentof the filter, so that the lumen of the vessel is completely covered bythe filter and all blood flows through the filter.

Retraction and removal of the filter may be accomplished by reversingthe process of deployment, or by use of a separate, and typically alarger diameter capture sheath the capture sheath is advanced over the0.014 inch diameter segment of the filter device, the filter withdrawnproximally into the distal end of the capture sheath, and both devicesare removed together.

FIGS. 4A through 4J depict the design, deployment, use, and retrieval ofan alternative filter device for capturing debris that flow downstreamfrom an interventional site in a patient's vessel. FIG. 4A shows filter30 which takes on a substantially conical shape and is designed so thatits opening, or mouth 74, can expand to completely or nearly completelyfills the lumen of a vessel. The filter extends distally from mouth 74of the filter and provides an area where debris is trapped. The mouth offilter 30 may, in certain embodiment, include circular rim 77 which is aframe comprised of a bendable material, preferably a plastic orsuperelastic material, e.g., nitinol. Filter 30 is held in positionwithin a vessel by means of a plurality of tethers 76, wherein thenumber of tethers are two or more, more preferably three or more. Anindependently operable tether 75 is also attached to rim 77. The tethersare attached at equidistant points around the mouth of the filter.Tethers 76 extend proximally and are attached to elongate tubular member60. The tethers are of substantially equal lengths, such that the planedescribed by the mouth of the filter is maintained in a positionsubstantially perpendicular to the longitudinal axis of the vessel.Second elongate member 65 is slideably disposed within elongate tubularmember 60, and is attached to independently moveable tether 75 at adistal end of member 65. Tubular member 60 is sized to permit typicallytherapeutic and diagnostic devices to be delivered over the filterguidewire while the filter is deployed at a distal end.

As shown in FIG. 4B, during delivery and removal of the filter to andfrom its deployment site, capture sheath 70 is used to contain filter 30to prevent it from catching and injuring the vessel wall duringmovement, and to retain and remove from the patient debris captured bythe filter. Once the filter is at the region of interest, it is pushedfrom the distal end of capture sheath 70. To retrieve the filter, it ispulled back into capture sheath 70 and removed from the patient.Alternatively, separate delivery and retrieval sheaths may be used. Forexample, where a large amount of debris is collected by the filter, alarger diameter retrieval sheath may be required.

FIG. 4B shows filter 30 and tethers 76 folded and packaged within thecontainment area at the distal end of delivery sheath 70 and ready fordeployment within a region of interest a patient's vessel. In certainembodiments, the distal end 66 of tubular member 60 is larger indiameter than the body of tubular member 60 and acts as a plunger thatis used to push the filter out of the containment area at the distal endof sheath 70. FIG. 4D shows sheath 70 being pulled proximally relativeto tubular member 60, thereby causing the filter to be ejected from thedistal end of sheath 70. The filter begins to expand as it leaves thesheath. Alternatively, tubular member 60 may be pushed distally relativeto sheath 70 to cause ejection of filter 30.

FIG. 4E shows the filter fully ejected from sheath 70 and deployed.Filter mouth 74 completely or nearly completely fills the lumen of thevessel in which it is deployed. Circular rim 77, when use, aids in fullexpansion of the filter. FIG. 4F shows complete removal of sheath 70from tubular member 60 so that member 60 can act as a guidewire and isready to receive and provide support and guidance for other therapeuticdevices that are to be delivered to the area of interest within thevessel.

FIG. 4G shows the beginning of filter retrieval process. Elongate member65 is retracted proximally relatively to tubular member 60.Independently moveable tether 75 attached to elongate member 65 isthereby pulled proximally, and this action tilts the mouth of the filterfrom its fully deployed position and readies it to be pulled intocapture sheath 70. Just prior to retrieval, the plane described by themouth of the filter is positioned substantially parallel to thelongitudinal axis of the vessel. FIG. 4H shows capture sheath 70delivered over tubular member 60 and ready to be further advanced tocover filter 30 and the debris it contains. FIG. 4I shows capture sheath70 advancing and capturing filter 30. As filter 30 enters sheath 70, thefilter mouth folds upon itself in much the same manner as it was loadedinto sheath 70 before deployment. Alternatively, once the distal end ofsheath 70 has advanced to the filter, tubular member 60 and elongatemember 65 may be pulled proximally relative to sheath 70, thus pullingthe filter inside the distal end of sheath 70. FIG. 4J shows filter 30fully retracted inside the distal end of capture sheath 70. The entirefilter system can then be removed from the patient.

FIG. 5A depicts the filter device of FIG. 4C inserted within stenoticlesion 100 of vessel 101. FIG. 5B shows the filter device of FIG. 5Aafter deployment of filter 30 downstream stenotic lesion 100. Afterremoval of capture sheath 70, tubular member 60 serves as a guidewirefor delivering a therapeutic catheter, such as angioplasty catheter 200,as shown in FIG. 5C. Angioplasty catheter 200 includes balloon 205 in adistal region thereof, and carries tubular member 60 within guidewirelumen 210. Atherectomy and stent deployment catheters may alternativelybe used in place of or in addition of the angioplasty catheter depictedin FIG. 5C. After inflation of angioplasty balloon 205 to compressstenotic lesion 100, the balloon is deflated and the angioplastycatheter 200 is removed from the patient's vessel. Capture sheath 70 isthen advanced along tubular member 60 to retrieve filter 30 as shown inFIG. 5D.

FIGS. 6A through 61 depict the design, deployment, use, and retrieval ofanother filter device for capturing debris that flow downstream from aninterventional site in a patient's vessel. FIG. 6A shows the maincomponents of the filter and delivery system, while FIG. 6B shows thecapture sheath. Filter 30 in FIG. 6A is substantially conical anddesigned so that its opening, or mouth 91, expands to completely ornearly completely fill the lumen of a vessel. The filter material thenextends distally (downstream) from the mouth of the filter and providesan area where debris is captured. Filter 30 is held in position in avessel by flexible struts 90 attached at equidistant point around themouth of the filter. The flexible struts extend proximally to elongatemember 80 to which the struts are attached. A minimum of three flexiblestruts is needed, while five flexible struts are shown in FIG. 6A.

Struts 90 may be constructed of a superelastic material, preferably ashape memory material, such as nitinol. Struts 90 are preformed andattached to elongate member 80 so that when the struts are advanceddistally and freed from containment sheath 85. The struts then expandoutward to open mouth 91 of filter 30, so that the filter substantiallyfills the vessel in which it is deployed. The struts are ofsubstantially equal lengths so that the plane described by the mouth offilter 30 is maintained in a position substantially perpendicular to thelongitudinal axis of the vessel. Struts 90 may also be taper ground inany number of ways so that struts 90 are smaller at their distal endsand can more easily conform to the vessel wall.

Surrounding elongate member 80 is capture sheath 85. The majority of thelength of sheath 85, from its proximal end to near its distal end, has adiameter adapted to pass other interventional devices after the filterhas been deployed. As such, sheath 85 may also serve as a guide wire.During delivery and removal of filter to and from its deployment site,sheath 85 contains filter 30 to prevent it from catching or injuring thevessel wall, and to retain and remove from the patient debris capturedwithin the filter. When filter 30 reaches a region of interest, filter30 is pushed distally from the distal end of capture sheath 85. Toretrieve filter 30, the filter is pulled proximally into sheath 85, orsheath 85 is advanced over filter 30, and the combination is removedfrom the patient.

FIG. 6C shows filter 30 and struts 90 packaged within the containmentarea at the distal end of capture sheath 85. As shown, filter 30 isready for deployment. The distal end of sheath 85 has a larger diameterthan elongate member 80 to provide adequate space for storage of struts90, filter 30, and debris captured within filter 30.

FIG. 6D shows elongate member 80 being pushed distally relative tosheath 85, which causes filter 30 to be ejected from the distal end ofsheath 85. Slight rotation of elongate member 80 during deployment mayassist with deployment. Filter 30 begins to expand as it leaves sheath85. Alternatively, sheath 85 may be pulled proximally relatively toelongate member 80 to release filter 30.

FIG. 6E shows filter 30 fully ejected from sheath 85. Preformed struts90 are beginning to leave sheath 85 and are expanding outward to openmouth 91 of filter 30. FIG. 6F shows struts 90 completely free of sheath85 and fully expanding filter 30. Sheath 85 is now ready to function asa guidewire to receive and provide support for any other device,including therapeutic catheters, which are to be delivered to the regionof interest.

FIG. 6G shows the beginning of the filter retrieval process. Elongatemember 80 is pulled proximally relative to sheath 85, and this actioncauses struts 90 to begin collapsing as they enter the containment areaat the distal end of sheath 85. The filter mouth begins to close,trapping debris inside filter 30. FIG. 6H shows struts 90 completelywithdrawn sheath 85. As filter 30 begins to enter sheath 85, elongatemember 80 is rotated as it is pulled proximally. This twisting actionwinds filter 30 and compacts the filter, which assists re-enteringsheath 85. FIG. 6I shows filter 30 retracted inside the distal end ofsheath 85. Filter 30 has been twisted and compacted into its containmentarea. The entire filter system can now be removed from the patient'svessel.

The filtration devices described herein can be used not only asguidewires to receive and provide support for any other device, but mayalso be advanced through the guidewire lumen of a therapeutic catheteronce in place. For example, a conventional guidewire may be positionedwithin a vessel crossing a region of interest. A therapeutic catheter isthen advanced over the conventional guidewire so that the therapeuticinstrument lies within the region of interest. The conventionalguidewire is then withdrawn, and a guidewire filter as described hereinis advanced through the guidewire lumen of the therapeutic catheter.FIG. 7A, for example, shows stent deployment catheter 250 having stent255 disposed on a distal region, and positioned across stenotic lesion100 of vessel 101. The stent can be either self expanding or deployed bythe action of a dilatation balloon. A filter guidewire as shown in FIG.6C is advanced through guidewire lumen 260 of catheter 250 until filter30 passes distally beyond catheter 250 and downstream of lesion 100.Sheath 85 is withdrawn and filter 30 is deployed within vessel 101 asshown in FIG. 7B. Stent 255 is then expanded to increase the luminaldiameter across lesion 100, and catheter 250 is withdrawn from thevessel as shown in FIG. 7C. The filter is then captured by sheath 85 asdescribed in FIG. 6H, and the filter guidewire is removed from thepatient's vessel. Alternatively, therapeutic catheter 250, sheath 85,and filter 30 may be simultaneously removed after stent deployment.

Various percutaneous insertion sites for the filter devices disclosedherein are depicted in FIG. 8. The filter device can be inserted throughan incision on right subclavian artery 111, left subclavian artery 106,right brachial artery 118, left brachial artery 115, right femoralartery 125, or left femoral artery 120 to enter a patient's arterialcirculation. The double side-wire loop filter of FIG. 1H having elongatetubular member 10 is shown inserted through left subclavian artery 106or left femoral artery 120 and deployed within left common carotidartery 102. The filter device can also be inserted through an incisionon right subclavian vein 110, left subclavian vein 107, right cubitalvein 119, left cubital vein 116, right femoral vein 126, or left femoralvein 121 to enter a patient's venous circulation. The double side-wireloop filter of FIG. 1H is shown inserted through right subclavian vein110 and deployed within the superior vena cava. The double side-wireloop filter of FIG. 1H is also shown inserted through right femoral vein126 and deployed within the inferior vena cava.

The length of the elongate member which typically will serve as aguidewire is generally between 30 and 300 centimeters, preferablyapproximately between 50 and 180 centimeters. The outer diameter of theguidewire will generally be between 0.01 and 0.05 inches, preferablyapproximately between 0.014 and 0.035 inches. The filter will be capableof expanding to an outer diameter of at least 0.2 centimeters, morepreferably at least 0.5 centimeters, more preferably at least 1.0centimeters, more preferably at least 1.5 centimeters, more preferablyat least 2.0 centimeters, more preferably at least 2.5 centimeters, morepreferably at least 3.0 centimeters, more preferably at least 3.5centimeters, more preferably at least 4.0 centimeters, more preferablyat least 4.5 centimeters, more preferably at least 5.0 centimeters. Thefilter will be capable of contracting to an outer diameter of between0.05 and 2.0 millimeters, preferably approximately between 0.8 and 1.2millimeters. The outer diameter of the capture sheath will generally bebetween 0.5 and 2.2 millimeters, preferably approximately between 0.9and 1.9 millimeters. These ranges cover suitable diameters for bothpediatric and adult use. The foregoing ranges are set forth solely forthe purpose of illustrating typical device dimensions. The actualdimensions of a device constructed according to the principles of thepresent invention may obviously vary outside of the listed rangeswithout departing from those basic principles.

Although the foregoing invention has, for the purposes of clarity andunderstanding, been described in some detail by way of illustration andexample, it will be obvious that certain changes and modifications maybe practiced which will still fall within the scope of the appendedclaims. Moreover, it will be understood that each and every featuredescribed for any given embodiment or in any reference incorporatedherein, can be combined with any of the other embodiments describedherein.

1. An endovascular filter, comprising: an elongate tubular member havinga proximal end, a distal end, and a lumen therebetween, the lumencommunicating with a port at the distal end; and a continuous flexiblewire loop disposed within the lumen of the elongate tubular member, theloop having a first end, a second end, and an intermediate sectiondisposed between the first and second ends, the loop being positionednear the port of the elongate tubular member, the loop having a filterdisposed about the intermediate section, wherein the first end of theflexible loop is operated to advance the loop distally, the intermediatesection of the loop extends through the port and into a lumen of avessel, and the filter is thereby deployed.
 2. The filter of claim 1,further comprising a tether attached at one end to the intermediatesection of the flexible loop, wherein the tether restrains theintermediate section of the loop and changes the orientation of a planedescribed by the loop.
 3. The filter of claim 1, wherein the filtercomprises a mesh.
 4. The filter of claim 1, wherein the filter comprisesa thin filter having laser cut holes.
 5. The filter of claim 1, whereinthe flexible loop is a wire.
 6. The filter of claim 2, wherein thetether is a wire.
 7. The filter of claim 1, wherein the elongate tubularmember is a guidewire.
 8. A method for performing an endoluminalprocedure, comprising the steps of: providing an endovascular filtercomprising an elongate tubular member having a proximal end, a distalend, and a lumen communicating with a distal port, the elongate tubularmember having a continuous flexible wire loop disposed within the lumenof the elongate tubular member, the loop having a first end, a secondend, and an intermediate section disposed between the first and secondends, the loop having a filter disposed thereon; inserting theendovascular filter into a patient's vessel; positioning the filter at aregion of interest; and advancing distally the first end of the loop sothat the intermediate section of the loop extends from the port of theelongate tubular member, and the filter covers the lumen of the vessel.9. The method of claim 8, wherein the endovascular filter furthercomprises a tether attached at one end to the intermediate section ofthe flexible loop, wherein the tether restrains the intermediate sectionof the loop and changes the orientation of a plane described by theloop.
 10. The method of claim 8, wherein the filter comprises a mesh.11. The method of claim 8, wherein the filter comprises a thin filmhaving laser cut holes.
 12. The method of claim 8, wherein the flexibleloop is a wire.
 13. The method of claim 9, wherein the tether is a wire.14. The method of claim 8, wherein the elongate tubular member is aguidewire.
 15. The method of claim 10, wherein the endovascular filterfurther comprises a capture sheath slideably disposed about the mesh.16. The method of claim 8, further comprising the step of performingangioplasty.
 17. The method of claim 8, further comprising the step ofperforming stent deployment.